Belief is a mental representation, treated in various academic disciplines, especially philosophy and psychology, of a sentient being's attitude toward the likelihood or truth of something.[1] This notion of belief may represent a secularized common sense, but clashes violently with, for instant, the philosopher Martin Heidegger which in a passage concerning presence and presence in the representation of representing "We cannot scientifically prove the translation nor ought we simply by virtue of any authority trust in it (glauben). The reach of proof is too short. Belief has no place in thinking (Der Glaube hat im Denken keinen Platz)[2] The one notion excludes the other. From Greek two different concepts are often represented by the concept of belief: Pistis and Doxa. Simplified we may say that the first deals in trust and confidence, the latter in opinion and acceptance.

Epistemology is the philosophical study of knowledge, or more literally the process of understanding. The primary problem in epistemology is to understand exactly what is needed in order for us to have knowledge. In a notion derived from Plato's dialogue Theaetetus, where the epistemology of Socrates (Platon) most clearly departs from that of the sophists, who at the time of Plato seems to have defined knowledge as what here expressed as "justified true belief". The tendency to translate from belief (here: doxa - common opinion) to knowledge (here: episteme), which Platon (e.g. Socrates of the dialogue) utterly dismisses, results from failing to distinguish a dispositive belief (gr. 'doxa', not 'pistis') from knowledge (episteme) when the opinion is regarded true (here: orthé), in terms of right, and juristically so (according to the premises of the dialogue). Which was the task of the rhetors to prove. Plato dismisses this possibility of an affirmative relation between belief (i.e. opinion) and knowledge even when the one who opines grounds his belief on the rule, and are able to add justification (gr. logos: reasonable and necessarily plausible assertions/evidence/guidance) to it [3].[3] It is important to keep in mind that the sort of belief in the context of Theaetetus is not derived from the theological concept of belief, which is pistis, but doxa, which in theological terms refers to acceptance in the form of praise and glory.

Strangely, or not, Plato has been credited for the "justified true belief" theory of knowledge, even though Plato in the Theaetetus (dialogue) elegantly dismisses it, and even posits this argument of Socrates as a cause for his death penalty . Among American epistemologists, Gettier (1963)[4] and Goldman (1967),[5] have questioned the "justified true belief" definition, and challenged the "sophists" of their time.

Mainstream psychology and related disciplines have traditionally treated belief as if it were the simplest form of mental representation and therefore one of the building blocks of conscious thought. Philosophers have tended to be more abstract in their analysis, and much of the work examining the viability of the belief concept stems from philosophical analysis.

The concept of belief presumes a subject (the believer) and an object of belief (the proposition). So, like other propositional attitudes, belief implies the existence of mental states and intentionality, both of which are hotly debated topics in the philosophy of mind, whose foundations and relation to brain states are still controversial.

Beliefs are sometimes divided into core beliefs (that are actively thought about) and dispositional beliefs (that may be ascribed to someone who has not thought about the issue). For example, if asked "do you believe tigers wear pink pajamas?" a person might answer that they do not, despite the fact they may never have thought about this situation before.[6]

This has important implications for understanding the neuropsychology and neuroscience of belief. If the concept of belief is incoherent, then any attempt to find the underlying neural processes that support it will fail.

Philosopher Lynne Rudder Baker has outlined four main contemporary approaches to belief in her controversial book Saving Belief:[7]

Our common-sense understanding of belief is correct - Sometimes called the "mental sentence theory," in this conception, beliefs exist as coherent entities, and the way we talk about them in everyday life is a valid basis for scientific endeavour. Jerry Fodor is one of the principal defenders of this point of view.

Our common-sense understanding of belief may not be entirely correct, but it is close enough to make some useful predictions - This view argues that we will eventually reject the idea of belief as we use it now, but that there may be a correlation between what we take to be a belief when someone says "I believe that snow is white" and how a future theory of psychology will explain this behaviour. Most notably, philosopher Stephen Stich has argued for this particular understanding of belief.

Our common-sense understanding of belief is entirely wrong and will be completely superseded by a radically different theory that will have no use for the concept of belief as we know it - Known as eliminativism, this view (most notably proposed by Paul and Patricia Churchland) argues that the concept of belief is like obsolete theories of times past such as the four humours theory of medicine, or the phlogiston theory of combustion. In these cases science hasn't provided us with a more detailed account of these theories, but completely rejected them as valid scientific concepts to be replaced by entirely different accounts. The Churchlands argue that our common-sense concept of belief is similar in that as we discover more about neuroscience and the brain, the inevitable conclusion will be to reject the belief hypothesis in its entirety.

Our common-sense understanding of belief is entirely wrong; however, treating people, animals, and even computers as if they had beliefs is often a successful strategy - The major proponents of this view, Daniel Dennett and Lynne Rudder Baker, are both eliminativists in that they hold that beliefs are not a scientifically valid concept, but they don't go as far as rejecting the concept of belief as a predictive device. Dennett gives the example of playing a computer at chess. While few people would agree that the computer held beliefs, treating the computer as if it did (e.g. that the computer believes that taking the opposition's queen will give it a considerable advantage) is likely to be a successful and predictive strategy. In this understanding of belief, named by Dennett the intentional stance, belief-based explanations of mind and behaviour are at a different level of explanation and are not reducible to those based on fundamental neuroscience, although both may be explanatory at their own level.

To "believe in" someone or something is a distinct concept from "believing-that." There are at least these types of belief-in:[8]

Commendatory / Faith - we may make an expression of 'faith' in respect of some performance by an agent X, when without prejudice to the truth value of the factual outcome or even confidence in X otherwise, we expect that specific performance. In particular self-confidence or faith in one's self is this kind of belief.

Existential claim - to claim belief in the existence of an entity or phenomenon in a general way with the implied need to justify its claim to existence. It is often used when the entity is not real, or its existence is in doubt. "He believes in witches and ghosts" or "many children believe in Santa Claus" or "I believe in a deity" are typical examples.[9] The linguistic form is distinct from the assertion of the truth of a proposition since verification is either considered impossible/irrelevant or a counterfactual situation is assumed.

Insofar as the truth of belief is expressed in sentential and propositional form we are using the sense of belief-that rather than belief-in. Delusion arises when the truth value of the form is clearly nil.

Delusions are defined as beliefs in psychiatric diagnostic criteria[10] (for example in the Diagnostic and Statistical Manual of Mental Disorders). Psychiatrist and historian G.E. Berrios has challenged the view that delusions are genuine beliefs and instead labels them as "empty speech acts," where affected persons are motivated to express false or bizarre belief statements due to an underlying psychological disturbance. However, the majority of mental health professionals and researchers treat delusions as if they were genuine beliefs.

We are influenced by many factors that ripple through our minds as our beliefs form, evolve, and may eventually change

Psychologists study belief formation and the relationship between beliefs and actions. Three models of belief formation and change have been proposed:

The Conditional Inference Process

When people are asked to estimate the likelihood that a statement is true, they search their memory for information that has implications for the validity of this statement. Once this information has been identified, they estimate a) the likelihood that the statement would be true if the information were true, and b) the likelihood that the statement would be true if the information were false. If their estimates for these two probabilities differ, people average them, weighting each by the likelihood that the information is true and false (respectively). Thus, information bears directly on beliefs of another, related statement.[11]

Linear Models of Belief Formation

Unlike the previous model, this one takes into consideration the possibility of multiple factors influencing belief formation. Using regression procedures, this model predicts belief formation on the basis of several different pieces of information, with weights assigned to each piece on the basis of their relative importance.[11]

Information Processing Models of Belief Formation and Change

These models address the fact that the responses people have to belief-relevant information is unlikely to be predicted from the objective basis of the information that they can recall at the time their beliefs are reported. Instead, these responses reflect the number and meaning of the thoughts that people have about the message at the time that they encounter it.[11]

Some influences on people's belief formation include:

Internalization of beliefs during childhood, which can form and shape our beliefs in different domains. Albert Einstein is often quoted as having said that "Common sense is the collection of prejudices acquired by age eighteen." Political beliefs depend most strongly on the political beliefs most common in the community where we live.[12] Most individuals believe the religion they were taught in childhood.[13]

Charismatic leaders can form and/or modify beliefs (even if those beliefs fly in the face of all previous beliefs).[14] Is belief voluntary? Rational individuals need to reconcile their direct reality with any said belief; therefore, if belief is not present or possible, it reflects the fact that contradictions were necessarily overcome using cognitive dissonance.

Advertising can form or change beliefs through repetition, shock, and association with images of sex, love, beauty, and other strong positive emotions.[15] Contrary to intuition, a delay, known as the sleeper effect, instead of immediate succession may increase an advertisement’s ability to persuade viewer’s beliefs if a discounting cue is present.[16]

Physical trauma, especially to the head, can radically alter a person's beliefs.[17]

However, even educated people, well aware of the process by which beliefs form, still strongly cling to their beliefs, and act on those beliefs even against their own self-interest. In Anna Rowley's book, Leadership Therapy, she states "You want your beliefs to change. It's proof that you are keeping your eyes open, living fully, and welcoming everything that the world and people around you can teach you." This means that peoples' beliefs should evolve as they gain new experiences.[18]

Many motives may be manifestations of a more general one: to construct a perception of oneself and one's world to equip an individual with the ability to cope with life situations and ultimately lead a happy and successful life. Examples of motives include:

Accuracy and efficiency

This motivation refers to the degree to which people are motivated to construct an accurate perception of themselves and their environments. This motivation may also be related to people's desire to make quick judgments or decisions, thus the desire for quick judgment compromises the accuracy of one's beliefs.

Desirability

People are generally motivated to think well of themselves and the people they care about. Scholars postulate that people usually wish to maintain a positive view of themselves and the world in which they live. Consequently, people may be more likely to assume that positive events will occur and undesirable events are unlikely.

The "Just World"

Studies suggest that people are motivated to believe that they possess favorable attributes and, therefore, are better able to cope within the world in which they live. For example, participants read a case in which a person was the victim of rape. Half of the participants were shown nonsexual, aggressive images before reading the case, images that should provoke the idea of an unjust world (lynchings, dead soldiers, etc.). After viewing these images, the participants in this condition were more likely to claim that they believed the rapist was apprehended and that the victim was partly to blame (as opposed to participants in another condition who did not view the aggressive images).

Consistency

Consistency refers to the desire to maintain an initial consistency among one's various beliefs and opinions. This belief may be related to the motivation of constructing an accurate representation of the world. This motive may be conceptualized in multiple ways. It may be conceptualized in regards to the degree of compatibility of beliefs with constructed propositions that compose an implicit theory. This motive may also be conceptualized as a motive that only arises when cognitive inconsistency occurs and people recognize it.

Justified true belief is a definition of knowledge that is most frequently credited to Plato and his dialogues.[19] The concept of justified true belief states that in order to know that a given proposition is true, one must not only believe the relevant true proposition, but also have justification for doing so. In more formal terms, a subject knows that a proposition is true if and only if:

This theory of knowledge suffered a significant setback with the discovery of Gettier problems, situations in which the above conditions were seemingly met but that many philosophers disagree that anything is known.[20]Robert Nozick suggested a clarification of "justification" which he believed eliminates the problem: the justification has to be such that were the justification false, the knowledge would be false. If so we can say belief becomes knowledge (accepted reality) when it is justified.

An extensive amount of scientific research and philosophical discussion exists around the modification of beliefs, which is commonly referred to as belief revision. Generally speaking, the process of belief revision entails the believer weighing the set of truths and/or evidence, and the dominance of a set of truths or evidence on an alternative to a held belief can lead to revision. One process of belief revision is Bayesian updating and is often referenced for its mathematical basis and conceptual simplicity. However, such a process may not be representative for individuals whose beliefs are not easily characterized as probabilistic.

There are several techniques for individuals or groups to change the beliefs of others; these methods generally fall under the umbrella of persuasion. Persuasion can take on more specific forms such as consciousness raising when considered in an activist or political context. Belief modification may also occur as a result of the experience of outcomes. Because goals are based, in part on beliefs, the success or failure at a particular goal may contribute to modification of beliefs that supported the original goal.

Whether or not belief modification actually occurs is dependent not only on the extent of truths or evidence for the alternative belief, but also characteristics outside the specific truths or evidence. This includes, but is not limited to: the source characteristics of the message, such as credibility; social pressures; the anticipated consequences of a modification; or the ability of the individual or group to act on the modification. Therefore, individuals seeking to achieve belief modification in themselves or others need to consider all possible forms of resistance to belief revision.

Without qualification, "belief" normally implies a lack of doubt, especially insofar as it is a designation of a life stance. In practical everyday use however, belief is normally partial and retractable with varying degrees of certainty.

Different psychological models have tried to predict people's beliefs and some of them try to estimate the exact probabilities of beliefs. For example, Robert Wyer developed a model of subjective probabilities.[21][22] When people rate the likelihood of a certain statement (e.g., "It will rain tomorrow"), this rating can be seen as a subjective probability value. The subjective probability model posits that these subjective probabilities follow the same rules as objective probabilities. For example, the law of total probability might be applied to predict a subjective probability value. Wyer found that this model produces relatively accurate predictions for probabilities of single events and for changes in these probabilities, but that the probabilities of several beliefs linked by "and" or "or" do not follow the model as well.[21][22]

A "belief system" is a set of mutually supportive beliefs. The beliefs of any such system can be classified as religious, philosophical, ideological, or a combination of these. Philosopher Jonathan Glover says that beliefs are always part of a belief system, and that tenanted belief systems are difficult for the tenants to completely revise or reject.[23][24]

Philosopher Jonathan Glover warns that belief systems are like whole boats in the water; it is extremely difficult to alter them all at once (e.g., it may be too stressful, or people may maintain their biases without realizing it).[23]

The British philosopher Stephen Law has described some belief systems (including belief in homeopathy, psychic powers, and alien abduction) as "claptrap" and said that they "draw people in and hold them captive so they become willing slaves to victory... if you get sucked in, it can be extremely difficult to think your way clear again".[25]

A collective belief is referred to when people speak of what 'we' believe when this is not simply elliptical for what 'we all' believe.

SociologistÉmile Durkheim wrote of collective beliefs and proposed that they, like all 'social facts', 'inhered in' social groups as opposed to individual persons. Durkheim's discussion of collective belief, though suggestive, is relatively obscure.

PhilosopherMargaret Gilbert has offered a related account in terms of the joint commitment of a number of persons to accept a certain belief as a body. According to this account, individuals who together collectively believe something need not personally believe it themselves. Gilbert's work on the topic has stimulated a developing literature among philosophers. One question that has arisen is whether and how philosophical accounts of belief in general need to be sensitive to the possibility of collective belief.

Jonathan Glover believes that he and other philosophers ought to play some role in starting dialogues between people with deeply held, opposing beliefs, especially if there is risk of violence. Glover also believes that philosophy can offer insights about beliefs that would be relevant to such dialogue.

Glover suggests that beliefs have to be considered holistically, and that no belief exists in isolation in the mind of the believer. It always implicates and relates to other beliefs.[23] Glover provides the example of a patient with an illness who returns to a doctor, but the doctor says that the prescribed medicine is not working. At that point, the patient has a great deal of flexibility in choosing what beliefs to keep or reject: the patient could believe that the doctor is incompetent, that the doctor's assistants made a mistake, that the patient's own body is unique in some unexpected way, that Western medicine is ineffective, or even that Western science is entirely unable to discover truths about ailments.[23]

Glover maintains that any person can continue to hold any belief if they would really like to[23] (e.g., with help from ad hoc hypotheses). One belief can be held fixed, and other beliefs will be altered around it. Glover warns that some beliefs may not be entirely explicitly believed (e.g., some people may not realize they have racist belief systems adopted from their environment as a child). Glover believes that people tend to first realize that beliefs can change, and may be contingent on our upbringing, around age 12 or 15.[23]

Glover emphasizes that beliefs are difficult to change. He says that we may try to rebuild our beliefs on more secure foundations (axioms), like building a new house, but warns that this may not be possible. Glover offers the example of René Descartes, saying about Descartes that "[h]e starts off with the characteristic beliefs of a 17th-century Frenchman; he then junks the lot, he rebuilds the system, and somehow it looks a lot like the beliefs of a 17th-century Frenchman." To Glover, belief systems are not like houses but are instead like boats. As Glover puts it: "Maybe the whole thing needs rebuilding, but inevitably at any point you have to keep enough of it intact to keep floating."[23]

Glover's final message is that if people talk about their beliefs, they may find more deep, relevant, philosophical ways in which they disagree (e.g., less obvious beliefs, or more deeply held beliefs). Glover thinks that people often manage to find agreements and consensus through philosophy. He says that at the very least, if people do not convert each other, they will hold their own beliefs more openmindedly and will be less likely to go to war over conflicting beliefs.[23][26]